Summary of test results on tyre noise as affected by chassis, coachwork, tyre patterns, load, and road surfaces.
| Identifier | ExFiles\Box 156\3\ scan0032 | |
| Date | 30th October 1935 guessed | |
| -3- Summarised, the position as far as our tests have gone at the moment is as follows :- Tyre noise is affected by the following :- Percentage of Noise (Comparative) (1) Different types of Chassis Cadillac Graham 25 HP.RR. Ph.II.RR. Ph.III.RR. Nil. 5% 10% 25% 40% (2) Different Coachwork on same Chassis. 30-EX 33-EX 34-EX 20% 25% 50% (3) Difference in Tyre Patterns. Avon Supreme Goodrich (B.T.R.) Dunlop Original '90' Type 10% 20% 20% Dunlop Silent Dunlop Present '90' Type IndiaProduction 20 HP. with 4-speed box and Front Wheel Brakes Super 35% 40% 40% IndiaProduction 20 HP. with 4-speed box and Front Wheel Brakes Super after 3,000 miles. 60% (4) Difference in Load and Inflation Pressures. Greater the load - greater the noise. Lower the pressures - greater the noise. (5) Difference in Road Surfaces. | ||
From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).